The real difference between steel structure, space frame and steel truss

Steel space frame belong to spatial structural systems, and overall force and spatial deformation should be considered during calculations. Steel structure trusses are similar to plane steel trusses and are unidirectional force structures. As long as the strength and stability within the plane are calculated, the stability outside the plane is mainly borne by struts and tie rods.

Compared with steel space frame structures, steel truss structures omit the lower chord longitudinal rods and the ball nodes of the space. Steel truss structures are developed on the basis of steel space frame structures. Compared with space frame, truss structures are more economical.

Steel joist: It is generally in-span in-plane restrained, and its perpendicular direction is purlin or bracing, or unidirectional structure. It does not consider out-of-plane restraint, the connection form is welding, and the main material is steel section. The more common steel joist projects are such as large stadium, train station, high speed rail station roof steel joist.

Steel mesh frame: It is a two-way structure, supported and restrained in two directions or more. The connection form is bolt ball, and the main material is round tube. More common representative projects such as gas station canopy steel structure space frame. Large-scale dry coal shed space frame structure.

The use of steel structure materials and structural forms and structural systems are different from each other:

First of all, from the connection mode:

1.Mesh structure node is regarded as articulated, usually bolted.

2.Steel structure node is regarded as rigid joints, usually with welding.Second, from the use of materials and forms:

1.Steel structure is said in terms of structural material.

2.Space frame is said in the form of structure.

Space frame can be steel space frame, aluminum alloy space frame, etc., but steel space frame is mostly used in actual applications. In addition to steel space frame, steel structures also have various forms such as steel frames and steel portal frames.

In addition to steel space frame, steel structure also has steel frame, steel gantry and other forms.

Third, from the structural system:

1.Steel truss belongs to space structure system, and the overall force and space deformation should be considered in the calculation;

2.Steel truss is similar to plane steel truss, which belongs to unidirectional force structure, as long as the strength and stability in plane are calculated, the stability outside plane mainly relies on the brace and bollard to bear.

Advantages of mesh and shell structure

Mesh-shell structure is a space-like shell structure, or curved space frame structure, its shape is a shell, its composition is grid-like, it is a gridded shell, and it is also a shell-shaped space frame.

Characteristics of mesh-shell structure

(1) The rods of mesh and shell structure mainly bear axial force, the distribution of internal force in the structure is relatively uniform, and the stress peak is small, so it can give full play to the role of material strength.

(2) Because it can adopt various curved forms of shell structure, it can have rich modeling in appearance as thin shell structure, whether it is building plane or building form, mesh shell structure can give designers full design freedom and imagination space, by making steel structure contrast between motion and static, contrast between light and dark, contrast between reality and falsehood, organically combining architectural beauty and structural beauty, so as to make the building more easy to harmonize with the environment.

(3) Since the size of the rod is very small compared with a whole mesh-shell structure, the mesh-shell structure can be approximated as an isotropic or anisotropic continuum, and the results of the analysis of the reinforced concrete thin-shell structure are utilized to carry out qualitative analysis.

(4) The rods of the mesh in the mesh-shell structure can replace the curved rods with straight rods, i.e., replace the curved surfaces with folded surfaces, and if the rods are properly arranged and constructed, they can have good stress performance similar to that of the thin-shell structure. At the same time, it is easy to manufacture and install on site, and has the same superiority with flat plate mesh structure in structure and construction method.Mesh-shell structure is categorized according to the arrangement of rods: single-layer mesh-shell structure and double-layer mesh-shell structure two forms, generally speaking, small and medium-sized span (generally 40m or less) can be used in single-layer mesh-shell structure, double-layer mesh-shell structure is used in large spans. Single-layer mesh shell has better technical and economic indexes because of fewer rods, light weight, simple nodes and convenient construction. However, single-layer mesh shell has poor external stiffness and stability of curved surfaces, and various factors will have obvious influence on the internal force and deformation of the structure, therefore, attention must be paid to the arrangement of structural rods, the selection of roofing materials, the determination of calculation mode, the implementation of structural measures and the installation of structural construction, which can withstand a certain degree of stress, and the double-layer mesh shell can withstand a certain degree of stress. The double-layer mesh shell can withstand a certain bending moment and has high stability and loading force. When the roof needs to be installed lighting, sound and other kinds of equipment and pipeline, the choice of double space frame can effectively utilize the space, convenient ceiling or ceiling construction, economic and reasonable, double space shell according to the thickness of different, there are equal thickness and variable thickness of the points.